Array of Arrays in Perl

The following code snippet provides the often-saught Array of Arrays in Perl. This is my take on the Array of Arrays exercise from the book of Intermediate Perl, also known as the Alpaca book.

sub check_required_items {

  my $who = shift;
  my $items = shift;

  my %whose_items = map { $_, 1 } @$items;

  my @required = qw(preserver sunscreen water_bottle jacket);
  my @missing = ( );

  for my $item (@required) {
    unless ($whose_items{$item}) {
      print "$who is missing $item.\n";
      push @missing, $item;
    }
  }

  if(@missing) {
    print "Adding @missing to @$items for $who.\n";
    push @$items, @missing;
  }
}

sub check_items_for_all {
  my $all_with_names_ref = shift;
  foreach my $person (keys %$all_with_names_ref) {    
    check_required_items($person,\@{$$all_with_names_ref{$person}});
  }
}

my @gilligan = qw(red_shirt hat lucky_socks water_bottle);
my @skipper = qw(blue_shirt hat jacket preserver sunscreen);
my @professor = qw(sunscreen water_bottle slide_rule batteries radio);

my %all = (  
  Gilligan => \@gilligan,
  Skipper => \@skipper,
  Professor => \@professor,  
);

check_items_for_all(\%all);